Antarctic Wildlife at Risk From Overfishing, Experts Say

"Antarctic krill remains the largest exploitable stock and its exploitation also poses the greatest threat to the ecosystem," said krill expert Stephen Nicol, from the Australian Antarctic Division in Tasmania.

"A challenge for CCAMLR will be to ensure this huge potential catch is distributed in a way that does not adversely affect populations of land-based krill-feeding seals and sea birds."

Nicol identifies rapid growth in the fish farming and biotechnology industries as two key threats to sustainable harvests.

He says fish farming is expanding at a rate of 11 percent each year. In a decade, output is expected to exceed catches from ocean fisheries and overtake global beef production within 20 years.

"Aquaculture is going to become a very hungry animal and will require very large quantities of marine-based protein and oil," Nicol added.

Fish farming currently consumes 70 percent of the world's fish oil supply and 34 percent of total fishmeal, according to the Worldwide Fund for Nature, with stocks in many Atlantic and Pacific fisheries already in danger of collapse. Fish feed producers are now looking at Antarctic krill to meet future demand.

Incentives to use this natural pigment in salmon feed have risen recently due to consumer concerns over an artificially produced alternative. This year the European Union cut permitted levels of canthaxanthin (a coloring agent added to the feed of farmed salmon and trout to enhance the color of the flesh) by two-thirds after research revealed it could cause eye damage.

Nicol says the burgeoning biotechnology industry could place similar pressures on krill.

Drug companies claim it contains substances that can treat a range of human ailments, including heart disease, premenstrual tension, and skin cancer. Patents are pending for various krill-based medications.

While the Southern Ocean krill fishery is still in its infancy, scientists say Patagonian toothfish catches have already reached unsustainable levels.

Pressure on Toothfish

Economic factors elsewhere, including over-exploitation of North Atlantic cod stocks, have fueled a massive increase in fishing pressure.

A slow-maturing species that doesn't breed until ten years old, a single fish can fetch U.S $1,000.

Also known as "white gold," such prices have tempted "pirate" fishermen to follow legitimate vessels south in search of the fish.

Croxall said: "There's no doubt that in some places toothfish populations are on the point of collapse."

Last year's estimated illegal catch in CCAMLR waters was almost 11,000 tonnes (12,125 tons), with another 14,700 tonnes (16,205 tons) coming from adjacent high seas areas.

Nicol says policing pirate vessels is extremely difficult, adding, "The main problem is the vast area you've got to cover down there. Illegal fishing is a highly organized activity that involves multinationals."

Australian authorities have discovered illegal operators employ sophisticated techniques to avoid detection, including trans-shipment of fish and refuelling at sea.

The ecological damage caused by unregulated fishing isn't confined to toothfish. CCAMLR estimates pirate longlining vessels have killed up to 144,000 albatrosses and 400,000 petrels in Antarctic waters since 1996.

Longlining is a fishing method that uses thousands of baited hookshooks that can also catch feeding sea birds.

Croxall said : "10,000 to 20,000 hooks are set each day by these vessels on lines several kilometers long. In 20 to 30 years' time there's going to be an inexorable decline in albatross numbers."

Scientists now want the international community to act to safeguard krill and toothfish stocks throughout the Southern Ocean, otherwise its albatross, penguin, seal, and whale populations could all be left living on very thin ice.